As of the census[1] of 2000, there were 1,278 people, 485 households, and 354 families residing in the city. The population density was 1,307.2 people per square mile (503.5/km2). There were 542 housing units at an average density of 554.4/sq mi (213.5/km2). The racial makeup of the city was 83.26% White, 6.81% African American, 0.78% Native American, 0.16% Asian, 6.18% from other races, and 2.82% from two or more races. Hispanic or Latino of any race were 17.14% of the population.

There were 485 households out of which 36.1% had children under the age of 18 living with them, 54.6% were married couples living together, 12.6% had a female householder with no husband present, and 27.0% were non-families. 24.5% of all households were made up of individuals and 13.8% had someone living alone who was 65 years of age or older. The average household size was 2.64 and the average family size was 3.10.

In the city the population was spread out with 29.7% under the age of 18, 7.8% from 18 to 24, 27.2% from 25 to 44, 20.7% from 45 to 64, and 14.5% who were 65 years of age or older. The median age was 35 years. For every 100 females there were 97.8 males. For every 100 females age 18 and over, there were 85.9 males.

The median income for a household in the city was $33,684, and the median income for a family was $40,625. Males had a median income of $33,125 versus $21,786 for females. The per capita income for the city was $18,722. About 4.5% of families and 9.3% of the population were below the poverty line, including 8.9% of those under age 18 and 21.0% of those age 65 or over.

St. Paul Lutheran Church in Thorndale, established in 1891, has a school and a cemetery to the rear of the sanctuary. Its services were originally in German. The current pastor is James K. Mann (2011).

Thorndale has a number of churches, representing several denominations. Pleasant Retreat United Methodist Church (Texas Annual Conference), St. Paul Lutheran Church (Missouri Synod), St. John Lutheran Church (ELCA), First Baptist Church of Thorndale (FBC), Shiloh Baptist Church (SBC) and Mount Zion Baptist Church (National Baptist) are the main congregations serving Thorndale.

Thorndale (along with Thrall, Taylor, and Round Rock to the west) was where the vast majority of the principal photography and locations for the 2002 movie The Rookie, starring Dennis Quaid, and Rachel Griffiths, were filmed. The Thorndale High School baseball stadium, the downtown main street, and other parts of town were integral to the film, with Thorndale cast as "Big Lake, Texas". Local resident Emanuel Castillo's role in the film was to throw the baseball when Dennis Quaid was on the mound. Other local residents also appeared in the film as extras. Thorndale has also served as location for a number of other films and other productions.

The The Apache Pass Amphitheater and Festival Grounds is located five miles north of Thorndale on Ranch Road 908, just off Ranch Road 486. Apache Pass hosts a number of major events each year.,[7] including Christian music festivals and the eastern edition of the Nocturnal Wonderland (formerly known as the Nocturnal Fest), one of the largest electronic music festivals in the United States which found 50,000 musical enthusiasts attending in 2012.[7][8] Apache Pass also hosts the Annual Texas Trail Riders Convention and Trail Ride and the Annual Silver Spurs Spring Jam, which benefits the SS BEVO Endowment, which has been established to fund the care and expenses of BEVO (the UT Longhorn steer mascot), provides scholarships for UT students and supports the University of Texas Neighborhood Longhorns program. Apache Pass also hosts a number of local events and concerts, and has become a vital part of the Thorndale community and its tradition of the arts, music and film. Apache Pass also has a historical museum dedicated to the Apache nation and the contribution of native Americans in the history of Texas.[9]